TW200908030A - Stacked PTC thermistor and process for its production - Google Patents

Abstract

A stacked PTC thermistor comprises a body 4 obtained by alternating lamination of a semiconductor ceramic layer 2 and an internal electrode 3, and a pair of external electrodes 5a, 5b provided at the edge faces 4a, 4b of the body 4 and electrically connected with the internal electrode 3. The semiconductor ceramic layer 2 is composed of a porous sintered compact containing crystal grains of a barium titanate-based compound, and an alkali metal element is preferentially distributed in at least one of the grain boundaries and voids of the sintered compact.

Description

200908030 IX. Description of the Invention: [Technical Field] The present invention relates to a laminated PTC thermistor and a method of manufacturing the same. [Prior Art]

As the thermistor, a PTC (P〇sitive Temperature Coefficient) thermistor having a positive resistance temperature characteristic, that is, an electric resistance which increases with an increase in temperature, is known. The pTC thermistor is used as a self-controlled heating element, an overcurrent protection element, and a temperature sensor. First, as such a PTC thermistor, a single-plate type ρτ〇 thermistor is used, and the single-plate type PTC thermistor includes a semiconductor ceramic layer in which a trace amount of a rare earth element or the like is added as a main The composition is barium titanate (BaTi〇3) and has electrical conductivity; and a pair of external electrodes sandwiching the semiconductor ceramic layer. In recent years, in order to suppress power consumption, the PTC thermistor has been strongly expected to reduce the resistivity at a normal temperature state during non-actuation (hereinafter, referred to as "room temperature resistivity" for convenience). Due to the PTC thermistor, the larger the electrode area, the more the room temperature resistivity is inversely proportional to the electrode area, and the room temperature resistivity is reduced. Therefore, as a resistor for replacing the conventional single-plate type PTC varistor, a laminated PTC thermistor in which a plurality of semiconductor ceramic layers, a plurality of layers, and a plurality of internal electrodes are alternately laminated has been proposed. In the laminated PTC thermistor, since a plurality of internal electrodes can be laminated, the electrode area can be greatly increased, so that the room temperature resistivity can be lowered. An example of a laminated PTC thermistor is disclosed in Japanese Patent No. 3636075. The laminated PTC thermistor Bai Yu. Rain 7 double electric ugly including · electronic parts body, its intersection 131933.doc 200908030 for the laminated layer of barium titanate-based semiconductor ceramic layer and base metal internal electrode μ external electrode, Formed on the end surface of the electronic component body. The laminated PTC thermistor is formed by impregnating a glass component in an electronic component body. It is disclosed in Japanese Patent No. 3,366,075 that such a laminated PTC thermistor has low resistance and high voltage resistance. SUMMARY OF THE INVENTION However, for a PTC thermistor, 'in addition to requiring a low room temperature resistivity, 'there is a greater demand for a resistivity relative to the operation of the room temperature resistivity (below 'for convenience' The ratio of the "high-temperature resistivity" (hereinafter referred to as the "jump characteristic" for convenience. If the jump characteristic is large, the resistance change with respect to the temperature change becomes large, so that the operation can be performed more reliably. However, the inventors of the present invention have found that the laminated type p T c thermistor shown in the above-mentioned Japanese Patent No. 3 6 3 607, although the room temperature resistivity can be lowered, cannot be obtained. Fully characterized.

The present invention is directed to the above-mentioned problem. The object of the present invention is to provide a laminated type = thermistor capable of achieving both high room temperature resistivity and large jump characteristics at a high level. Further, an object of the present invention is to provide a method of manufacturing a laminated PTC thermistor having the above characteristics. In order to achieve the above object, the inventors of the present invention have found that the composition and structure of the semiconductor ceramic layer of the laminated PTC thermistor are intensively studied, and it has been found that the room temperature resistivity and the jumping characteristic can be balanced at a high level by controlling the fine structure. Japanese, that is, the present invention provides a laminated PTC thermistor, characterized in that it has a body which is alternately laminated with a semiconductor ceramic layer and an internal electric 131933.doc 200908030 pole 'and a pair of external electrodes' respectively Provided on the two end faces of the body and electrically connected to the internal electrodes, the semiconductive ceramic layer is composed of a porous sintered body containing crystal grains of a barium titanate-based compound, and the alkali metal elements are unevenly distributed on the crystal grains of the sintered body At least one of a boundary and a gap. In the laminated PTC thermistor as described above, since the alkali metal element is unevenly distributed in at least one of the crystal grain boundary of the crystal grain of the barium titanate-based compound and the void portion composed of the crystal grain, High level of room temperature resistivity and large jump characteristics. The reason why the above effects can be obtained is not determined, but the inventors of the present invention presume as follows. That is, since the alkali metal element is usually easily oxidized, the alkali metal element which is unevenly distributed in the grain boundary and the void portion of the crystal grain selectively adsorbs oxygen to the grain boundary or the void portion, or may form a base. Metal oxide. As a result, the low room temperature resistivity can be maintained and a large jump characteristic can be obtained. Further, the present invention provides a method of manufacturing a laminated PTC thermistor, which comprises a method of manufacturing a laminated PTC thermistor in which a semiconductor ceramic layer containing a barium titanate-based compound and an internal electrode are alternately laminated, including a first step of forming a laminate of a precursor layer of a semiconductor pottery layer and a precursor layer of an internal electrode; and a second step of firing a layered body in a reducing atmosphere to form a porous sintered body; The pot is attached to the sintered body by the metal component; in the fourth step, the sintered body to which the metal component is attached is reoxidized. In the above method for manufacturing a laminated PTC thermistor, by reoxidizing the sintered body obtained after firing, the grain boundary of the crystal grain of the 131933.doc 200908030 constituting the semiconductor Tauman layer is formed. Oxidized nearby. Sex. The reason for this is that the Schottky barrier of the electron capture is formed in this portion by causing the crystal grains s 5 to appear as PTC τ ^ and α ^ 卜 machi over-rolling. Then, in the present invention, the ruthenium platinum traces the metal to the sintered body after the formation of the system 1 and before the reoxidation, and the jump of the laminated PTC thermistor obtained by the stomach is particularly characteristic. It is not certain that the specific details of the addition of the ruthenium metal to the sintered body before the reoxidation step are uncertain, but the inventors of the present invention, etc., make the alkali metal component before the reoxidation step. Adhered to the inner body, the alkali metal component is likely to be segregated in the grain boundary formed in the sintered body or in a large number of voids (like 'β Β ^ , formed in the semiconductor ceramic = 少 less than 3 or less Grain boundaries between crystal grains). This month's special person believes that the above honest t 4 burning society! The method is segregated in the grain boundary of the alkali metal component in the magic, and the re-emulsification step of the mouth body. 1 乍 is a promoter for the adsorption of chemical adsorption to the grain boundary or the two gaps. Therefore, the oxidation of the grain boundaries or voids is promoted by the re-metallization, 隹a_u field, and 7' by the knives.付 Pay a big jump feature. However, the mechanism is not limited thereto. = The larger the jump characteristic of the laminated PTC thermistor is =. however? In the present invention, the m-th inspection of the metal in the reoxidation is performed by the sintered body in the fourth step, and in the fourth step, the grain boundaries of the crystal grains constituting the semiconductor ceramic layer are oxidized or dried. In this case, the intragranular particles of the barium titanate-based ceramics are oxidized, so that the entirety of the semiconductive ceramic layer can maintain low electric power. According to the present invention, the jumping characteristic of At entangled, η is sufficient to accumulate PTC heat The varistor resistance can also be kept to a practically small value. In the manufacturing method of the present invention, it is preferred that in the third step, the metal component containing the metal salt is attached to the sintered body by the solution (4) containing the metal salt. Thereby, it is possible to effectively make the metal element unevenness in the grain boundary or the void portion of the sintered body. In the production method of the invention, the above alkali metal salt is preferably selected from the group consisting of NaN〇3, Na〇H, Na2C〇3, and A. , l gamma,

At least one of the groups consisting of LiN〇3, U2S〇4, K〇H, KN〇3, and ^〇3. Since the alkali metal salt is easily dissolved in a solvent, the metal element can be easily distributed unevenly in the grain boundary or void of the sintered body. In the manufacturing method of the present month, the alkali metal salt The molecular weight is preferably 6〇130. Since the metal salt is easily segregated in the crystal grain boundary or the void portion of the sintered body, the alkali metal element can be more selectively and unevenly distributed in the grain boundary or the void portion. By virtue of this, it is possible to maintain a low room temperature resistivity and to obtain better jump characteristics. According to the present invention, it is possible to provide a laminated PTC thermistor having a low level of room temperature resistivity and a large jump characteristic at a high level. Further, it is possible to provide a method of manufacturing a laminated ptc thermistor having the above characteristics. [Embodiment] Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments. As shown in the figure, the 'layered PTC thermistor (4) has a rectangular parallelepiped shape, a semiconductor layer 2 and an internal electrode 3, and a pair of external electrodes 5a and 5b, which are respectively formed on the end faces of the body 4. Hey, servant. Further, the end faces 4a and 4b are perpendicular to the boundary surface between the semiconductor ceramic layer 2 and the internal electrode 3, and are parallel to a pair of faces of the body 4 in the lamination direction of the semiconductor ceramic layer 2 and the internal electrode 3. On the end face of the body 4, only one of the electrode end faces 3a of each of the internal electrodes 3 is alternately exposed. The electrode end faces & are located within the semiconductor ceramic layer 2 and are embedded in the body 4. The external electrode is on the end face of the body 4

4a is electrically connected to the electrode end faces 3& of the internal electrode 3. The external electrode % is electrically connected to the electrode end face of the internal electrode 3 on the end face 4b of the body 4. That is, the laminated PTC thermistor 1 includes a body 4 including a semiconductor ceramic layer 2 and mutually parallel (four) internal electrodes 3 embedded in the semiconductor ceramic layer 2; and external electric 5a, 5b, The main body end faces 4a, 4b are covered so as to be electrically connected to at least one electrode end face 3a of the plurality of internal electrodes 3. The bovine conductor ceramic layer 2 is composed of a sintered body containing a titanate lock 1 〇 3) a pottery (four) material as a main component, and contains a metal component. Specific examples of the main component of the semiconductor layer 2 include a rare earth element (selected from at least one element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, and Er). Part of 'and selected from v, Chan and. The constituents of the group are replaced by the part of the Ti position. Also, you can enter - change the ^ soil test class (4) to replace the part of the Ba position. The Curie temperature can be changed by placing a part of the heart. Further, the semiconductor ceramics may further contain SiO 2 or Mn 〇. As a suitable main component of the semiconductor ceramic layer 2, a compound represented by the following formula (1) is given by the following 131933.doc 200908030. (Ba,.xREx)a(Til yTMy)〇3 . . . (1) In the formula (1), RE represents a group selected from Y, La, Ce, pr,

At least one element of the group consisting of Sm, Gd, Dy, and Er. Further, Μ represents at least one element selected from the group consisting of V, Nb and "constituent. The general formula (1) represents a portion in which Ba is replaced by RE, and Ba is replaced by TM. One part of the position. In this embodiment

In the middle, a portion of the Ba position is replaced, and a part of the Ti position is replaced by tm, whereby a laminated PTC thermistor which exhibits low resistance and exhibits excellent pTc characteristics can be realized. In the general formula (1), \ and 7 respectively indicate the amount of the portion in which the position of Ba is replaced by RE, and the amount of the portion in which the position of Ti is replaced by TM, and x and y preferably satisfy the following formula (2) and (3). 0.001 <x<〇.〇〇3 (2) 0<y<0.002 (3) It is preferable that α of the molar ratio of the Ba position and the Ti position satisfies the following formula (4). Thereby, a larger jump characteristic can be obtained. 〇.99<α<1.1 In the present embodiment, ΜηΟ or SiO 2 [i.e., (TibyTMy)] 0.0015 mol was added. Further, in the compound represented by the general formula (1), the addition amount of the element mol ΜηΟ relative to the Ti position of the above formula (1) is preferably 〇〇〇5~ to further improve the PTC characteristics. . However, if the amount is too large, the room temperature resistivity will become too high to obtain a good PTC characteristic. 'There is a decrease in resistance with respect to temperature. 131933.doc -12- 200908030 NTC (NegatiVe Temperature From the viewpoint of promoting the sintering of the lanthanum lanthanide compound, the amount of Si 〇 2 added is preferably 0.1 〇 from the viewpoint of the element 1 mo1 of the Ti position of the above formula (1). · 3 m〇l.

The content of the barium titanate-based compound represented by the above formula (1) as a main component of the sintered body of the semiconductor ceramic layer 2 is preferably 95% with respect to the entire sintered body constituting the semiconductor ceramic layer 2 % or more, further preferably 98% by mass or more, more preferably 99% by volume or more. The higher the content, the more the moon has been able to take into account both low room temperature resistivity and large jump characteristics. The porosity of the sintered body constituting the semiconductor ceramic layer 2 is preferably from 5 to 25%, more preferably from 10 to 20%. By adjusting the void ratio to 5 to 25%, it is possible to achieve both low room temperature resistivity and large jump characteristics at a higher level. The jump characteristic in ~~=本本明明, for example, can be performed according to the following formula (7). Ten counts. The larger the value calculated by the following formula (7), the larger the jump characteristic and the more excellent the P T C characteristic. Jump characteristics = Log1G (R2 (10) / r25) (5)

Raoo : 200 ° C resistivity (high temperature resistivity) R25 : 25 ° C resistivity (room temperature resistivity) - π 々 , , 之 之 之 之 之 之 之 之 之 之 碱 碱 碱 碱 可 可 可 可 可 可 可 可 可 可 可 可 可 可 可The content of the alkali metal compound in terms of the alkali metal element is preferably 0,00, and 0.007 in terms of the element 1 of the above formula (1). If the content of the metal test compound is increased within this range, the jump characteristics can be further increased. On the other hand, if the content of the metal compound is reduced within the range of 13J933.doc 200908030, the room temperature resistivity can be further lowered. Fig. 2 is a result of elemental drawing based on an FE-EPMA (Electron Probe Microanalyzer) showing a fine structure of a semiconductor ceramic layer of the present invention and an example of a knives. In the sample system for analysis, a sintered body containing a barium titanate-based compound as a main component was immersed in an aqueous solution of Na2SiO3 (9.5 mass%), and then it was 7 Torr to 8 Torr in the atmosphere.半导体 The semiconductor ceramic layer constituting the laminated PTC thermistor obtained by reoxidation is further processed before the surface of the semiconductor ceramic layer is polished. Fig. 2(A) shows a photograph (10000 magnifications) of the fine structure (1 〇 μηη region) of the semiconductor ceramic layer. In Fig. 2(A), the white portion indicates crystal grains of a barium titanate-based compound as a main component, and the black portion indicates a void. As shown in the photograph, the sintered body constituting the semiconductor ceramic layer is porous. In other words, the semiconductor ceramic layer is composed of a porous sintered body containing a crystal grain of a barium titanate-based compound as a main component. Fig. 2 (Β) is a sodium element distribution corresponding to the semiconductor ceramic layer of the photograph of Fig. 2(A). In Fig. 2(B), the portion of white is the position where sodium is present. As a result of the distribution of the nano-element, the sodium element is unevenly distributed to the crystal grain boundary ' of the crystal grain of the barium titanate-based compound which is a main component of the sintered body constituting the semiconductor ceramic layer, and the void portion composed of the crystal grain. Further, it is considered that the sodium element in the void portion acts as a sodium compound such as sodium oxide and adheres to the wall surface of the void (i.e., the surface of the crystal grain). Fig. 2(C) is a distribution of germanium elements 131933.doc -14· 200908030 corresponding to the semiconductor ceramic layer of the photograph of Fig. 2(A). In ® 2 (C), the white part is the gentleman's 旲, cut-table, and position. (4): The bismuth titanate-based compound grain boundary, which is a main component of the red body constituting the semiconductor potent layer, and the space formed by the crystal grain (4). Further, the element of the cation of the granule is cut as an oxide (e.g., dioxo), and the void is attached to the wall surface of the void (i.e., the surface of the crystal granule). On the other hand, the internal electrode 3 is preferably a specific composition of the internal electrode 3 containing a base metal as a main component, and for example, it may be exemplified by 犯 or 妒 2 ^ > i_ * inch JN i combination. As a specific composition of the external electrodes 5a and 5b, Ag or an Ag-pd alloy or the like. α σ 牛牛 Next, a method of manufacturing a laminated pTc thermistor according to the present embodiment will be described.制造 The manufacturing method of the laminated PTC thermistor I of the present embodiment is, for example, as shown in FIG. 3, and the main steps thereof include a step of mixing a raw material such as a titanate pin (mixing step: step S11); and pre-burning and mixing a step of raw material (pre-burning step: step S12); a step of pulverizing the calcined raw material (pulverizing step 7 step S13); forming an alternate layered semiconductor ceramic layer precursor layer (referred to as "semiconductor ceramic precursor layer" a step of laminating the inner electrode precursor layer (hereinafter referred to as "internal electrode precursor layer") (forming step: step S14); removing the binder contained in the laminate (debonding step: step) Sl5); a step of firing a layered body after the step of debonding in a reducing environment to form a porous sintered body (firing step: step S16); and immersing the sintered body in a solution containing an alkali metal salt, a step of attaching a base 2 component to a sintered body (alkali metal adhesion step: step 131933.doc 15 200908030 S17)'· a step of drying a sintered body of a metal component (drying step. (4) s18); and burning after drying The step of reoxidation of the knot (again = step: step S19). The following steps are described in the order of the steps shown in Fig. 3.

C

J First, a raw material powder for forming a semiconductor ceramic layer is prepared. The raw material powder is composed of a phthalic acid-based ceramic material which is a main component of the semiconductor ceramic layer, or a compound which becomes the barium titanate ceramic material after the firing step or the reoxidation step. The latter compound may, for example, be an oxide or a salt (carbonate or nitrate) of each metal constituting the bismuth phthalate material. Further, in the case where the semiconductor ceramic layer 2 contains a rare earth element, it may be a compound containing a rare earth element in the raw material powder. Examples of the compound of the rare earth element include a compound (such as an oxide or a salt) selected from at least one element selected from the group consisting of YU, Pr, Nd, Sm, Gd, Dy, and Er. Further, the raw material powder may further contain a compound of an alkaline earth metal such as Sr, a compound selected from at least a compound of v, and a group of η, Si〇2 or Mn〇. After the respective raw material powders are separately weighed according to a specific amount, in the mixing step (step S11), each raw material powder is placed in a container made of nylon together with pure water and a ball for pulverization, and pulverized and mixed 4 to 8 After hours, it was dried to obtain a mixed powder. Then, in the calcination step (step S12), the mixed powder is pre-formed as needed, and then calcined at 1000 to 115 (about 5% to 5 hours under ambient temperature conditions of rc) to obtain a calcined body. After obtaining the calcined body, in the pulverization step (step S13), the calcined pre-fired I31933.doc 200908030 is pulverized to obtain a calcined powder. Then, the calcined powder is placed together with pure water and a pulverizing ball into a nylon. In the container, a specific amount of solvent, binder and plasticizer are added thereto, and mixed with η, 士丄口 for about 10 to 20 hours, thereby obtaining a smash for the specific viscosity of the green sheet. The polymer may further contain a specific amount of a dispersing agent as needed. Γ 继 Next, in the forming step (step S14), a layered body in which a semiconductor pot precursor layer and an internal electrode precursor layer are alternately laminated is formed. In the step, 'firstly, the raw material for the green sheet is coated on a vinegar or the like by a doctor blade method or the like to dry it, and a green sheet (semiconductor ceramic precursor layer) is obtained. The thickness of the green sheet can be set. 10~100μπ1 left Right. For the upper surface of the green sheet obtained in the above manner, the internal electrode is printed by screen printing or the like (4). #This is formed on the green sheet (the semiconductor ceramic precursor layer) by the internal electrode. The internal electrode precursor layer is obtained by mixing and mixing the base metal powder with an electrically insulating material (varnish), for example, and a Ni alloy powder such as Ni powder or Ni-Pd can be used as the base metal powder. a plurality of laminated green sheets on which the internal electrode precursor layer is formed are stacked on the upper surface and the lower surface thereof without overlapping the inner electrode precursor layer. Then, using a laminator, pressure is applied from the lamination direction to perform pressing. The pressed body is obtained. Then, the compact is cut into the size of the mosquito using a shearing machine or the like, and the layered layer f is obtained in the forming step to form a structure of the stacked body PTC thermistor body 4 And a layered body is formed. That is, the 'stacked layer alternately has a green sheet (a semiconductor ceramic precursor layer) and an internal electrode precursor layer, and each of the internal electrode precursor layers is 131933.do c 200908030 The end face is exposed on the left end face or the right end face of the laminated body, and the other end face corresponding to the end face is sealed inside the laminated body. In the debonding agent step (step S15), the obtained laminated body is placed in 250 The liquid component such as the binder contained in the green sheet is removed from the laminate in the atmosphere of about ~6 〇〇t. Next, in the firing step (step S16), the reduction is performed at 1200 to 125 (r2). In the environment, the layered body after the debonding step is fired at 0.5 to 4 hours 从而 从而 to obtain a porous sintered body H, so-called reducing ring: ' means that at least does not oxidize on the internal electrode precursor layer The environment 'for example, can be a mixed environment of hydrogen and nitrogen. The base metal (such as Ni or a Ni alloy) contained in the internal electrode precursor layer is usually oxidized to reduce the function of the internal electrode. However, by laminating the laminate in a reducing atmosphere, it is possible to prevent the above. At the same time of oxidation, the laminate is sintered. The porosity of the porous sintered body obtained by the calcination step is preferably from 5 to 〜, and preferably from 1 to 〜. The void ratio of the sintered body is related to the laminated type pTc, the temperature resistivity of the sensitive resistor 1, and the PTC characteristics. When the porosity is less than 5%, the pTC characteristics tend to deteriorate. When the porosity exceeds :, the room temperature resistivity becomes large, and the pTc characteristic deteriorates. On the other hand, the crystal grain boundary of the crystal grains which the sintered body has can be appropriately formed by setting the porosity of the sintered body to the above-mentioned appropriate circumference. Oxidation. A porosity meter can be used to determine the void ratio of the sintered body. The main factor for changing the void ratio of the sintered body is the composition of the semiconductor layer or the firing condition of the laminate. In order to make the sintered body 131933.doc 200908030 porous, and to set the porous porosity to a suitable range, it is preferred that the composition of the semiconductor ceramic precursor layer is, for example, the following formulas (6) to (9). composition. Further, it is preferred to calcine the laminate in an environment of 1200 ° C, 1% H 2 /N 2 , and a dew point of 10 ° C. (Ba〇.997Gd〇.〇〇3)i.〇2Ti〇3+〇.〇5Si〇2+0.〇〇1 MnO (6) (Ba〇.9985Gd〇.〇〇i5)i.〇2( Ti 〇 998 998 998 998 998 998 998 998 998 998 〇i5)〇3 (8) (Ba〇.998Sm〇.. 2) 1.002Ti〇3 (9) After obtaining the porous sintered body by the firing step, in the alkali metal adhesion step (step S17), An alkali metal component such as an alkali metal adheres to the sintered body. The metal is preferably at least one of, for example, Li, Na, and K. The method of adhering the alkali metal component to the sintered body is not particularly limited, but a method of adhering the solution containing the alkali metal salt to the sintered body is preferred. Specifically, the sintered body is impregnated into a solution containing an alkali metal salt. By immersing the sintered body in a solution containing an alkali metal salt, since the solution penetrates into the sintered body, the alkali metal salt can be preferentially attached to the void in the sintered body containing the barium titanate-based compound as a main component. Department or grain boundary. The alkali metal salt is preferably at least one selected from the group consisting of NaN〇3, NaOH, Na2CO3, Na2SiO3, Li20, LiOH, LiN03, Li2S04, KOH, KN〇3 and & K2C〇3. These alkali metal salts are easily dissolved in a solvent such as water, and when the sintered body is impregnated into the solution, there is a tendency that it easily adheres to the void portion or the grain boundary of the sintered body. Further, in the method of manufacturing the laminated PTC thermistor 1 of the above embodiment, in the method of 131933.doc -19-200908030, it is preferred to use an alkali metal salt having a molecular weight of 80 to 13 Å, more preferably a molecular weight of Alkali metal salt of 84.995~122.063. The alkali metal salt having such a molecule is liable to be segregated in the grain boundary or the void portion of the sintered body, so that I can selectively distribute the alkali metal element unevenly in the grain boundary or the void portion. This makes it possible to more reliably achieve both low room temperature resistivity and large jump characteristics. Further, as an alkali metal salt attached to a particle of a barium titanate-based compound

The method 'in addition to the above methods' can also be exemplified by coating or spraying a cold liquid containing a metal salt. Further, the solution containing the metal salt is not particularly limited as long as the metal salt is soluble, and an aqueous solution or an organic solution may be used. The concentration of the metal salt in the metal salt solution is included. (4) The conversion of the metal element is preferably 〇.〇1~〇 〇8 m〇l%, more preferably (4)1~〇 m〇m. By using a 0 01~0 〇3 m〇1% alkali metal salt solution, the metal compound can be selectively segregated to the grain boundary portion or the void portion of the crystal grain of the sintered body, ## The internal metal salt concentration is adjusted to finally adjust the amount of the alkali metal compound contained in the sintered body. When the concentration of the alkali metal salt in the solution is too low, the amount of the alkali metal compound present in the crystal grain boundary or the void portion of the sintered body is insufficient, and the oxidation of the crystal grain boundaries of the crystal grains tends to be insufficient. Therefore, there is a tendency that the effect of increasing the jump characteristics cannot be sufficiently obtained. On the other hand, if the concentration of the metal salt in the solution is too high, the amount of the metal salt (10) attached to the sintered body has a tendency that, in the subsequent step, the metal intrusion into the particle Excessive oxygen is also present in the grains of the sintered body. 13I933.doc -20. 200908030 Therefore, there is a tendency for the low room temperature resistivity to be destroyed. After the k-junction: is cleaved in the solution containing the metal salt, the sintered body is dried in the drying step (step S18).

Next, in the reoxidation step (step S19), the dried sintered body is subjected to heat treatment in an oxygen atmosphere and reoxidized to obtain a bulk body 2. The conditions of the reoxidation are set to the extent that at least the obtained semiconductor ceramic layer 2_ can exhibit pTc characteristics, and: :. Oxidation occurs on the P electrode 3. The conditions for the reoxidation include various conditions such as the oxygen concentration in the oxidizing atmosphere, the heat treatment temperature, and the heat treatment time, but these conditions may be appropriately set depending on the size of the sintered body. A laminated PTC thermistor having an appropriate room temperature (IV) and PTC characteristics can be obtained by appropriately setting these conditions. Specifically, in the present embodiment, it is preferred to set the heat treatment temperature in the reoxidation step to be more preferably ~8 m:. If the treatment temperature is too low, the oxygen content of the crystal grain boundaries of the crystal grains of the sintered body is insufficient, and the effect of increasing the jump characteristics tends to be small. On the other hand, if the heat treatment temperature is too high, the internal electrode is oxidized, and the oxygen concentration of the oxidizing agent is preferably about 5% by volume, and the heat treatment time is preferably 5~2. Hours or so. In the reoxidation step, it is considered that the metal salt mainly adhering to the crystal grain boundary of the sintered body and the void portion in the metal adhesion step is oxidized depending on the case to become an oxide. Thereby, the obtained laminated PTC thermistor can attain a low level of room temperature resistivity and large jump characteristics at a higher level. After the reoxidation step, the materials for the external electrodes are respectively applied to the atmosphere of the 550 to 65 〇t after the end faces 4a and 4b of the 131933.doc • 21 · 200908030. Further, an external electrode is formed on the end surface. Further, the slurry for the external electrode may be an Ag paste or a ^pd bulk material, etc. As a result, a laminated PTC thermistor having the composition shown by ^ can be obtained. The method for producing a laminated pTC thermistor according to the above embodiment is to adhere the alkali metal salt to the crystal particles of the acid-based lock compound contained in the sintered body after the baking step and before the reoxidation step. Further, the vicinity of the grain boundary of the sintered body constituting the semiconductor ceramic layer 2 can be re-emulsified. As a result, the jump characteristics of the obtained laminated pTc thermistor can be increased. The larger the jump characteristic of the _' laminated PTC thermistor is, the larger the room temperature resistivity of the laminated PTC thermistor is. In the present embodiment, the metal salt is selectively made in the metal adhesion step. Attached to the grain boundary In the vicinity of 'selective oxidation of the vicinity of the grain boundary in the reoxidation step', the metal compound is segregated in the grain boundary. Thereby, the room temperature resistivity of the laminated PTC thermistor 1 can be maintained sufficiently low. In the laminated PTC thermistor PJL1 obtained by the above-described manufacturing method, the semiconductor ceramic layer 2 contains a barium titanate compound as a main component and a base as an auxiliary component. As shown in Fig. 2, the alkali gold component has a structure which is 'segregated at least one of a crystal grain boundary of a crystal grain of a barium titanate-based compound and a void portion formed of the crystal grain. The preferred embodiment of the laminated PTC thermistor of the present invention and the method of manufacturing the same has been described. However, the present invention is not necessarily limited to the above-described embodiment of I3I933.doc -22-200908030. For example, in the above method In the above, although the semiconductor ceramic precursor layer composed of green sheets, & and the internal electrode moon-J body layer composed of internal electrode paste are exemplified, Lane Peng, one turn + conductor Ceramic precursor layer and internal electrode precursor layer may be fired as long as the system or with A _ Nine times then become lice of the semiconductor ceramic layer and an inner electrode mound by persons, it is not necessarily limited to the above.

_In the metal adhesion step, the solution of the metal salt solution is attached to the metal salt, but the alkali metal salt may be directly attached without using the solution; and further, the laminated PTC thermistor is not limited In the above configuration, the number of layers of each layer or the position at which the internal electrodes are formed may be appropriately different. (Embodiment) Hereinafter, the present invention will be more specifically described based on examples and comparative examples, but the present invention is not The following examples are given. [Production of laminated PTC thermistor] (Example 1) First, as a raw material powder for forming a semiconductor ceramic layer, preparation

BaC03, Ti〇2, Gd203, SiO2, and Μη(Ν03)2 · 6H2〇. These raw material powders were weighed so that the obtained barium titanate-based compound became a composition of the above formula (6). The raw material powder to be weighed was placed in a container made of nylon together with pure water and a ball for pulverization, and mixed for 6 hours, followed by drying to obtain a mixed powder. Next, after preliminarily forming the mixed powder, it was placed in an atmosphere of 丨丨5〇〇c for 4 hours and pre-fired to obtain a pre-fired body. The pre-fired 131933.doc •23·200908030 was disintegrated and pulverized to obtain an average granulated gas, and the dinned j ancestor k was a pre-fired powder of 1 μηι. Then, the pre-baked powder is placed in a container made of nylon together with pure water and a ball for pulverization, and a solvent, a binder, and a plasticizer are added thereto, and the mixture after the addition is carried out by three rolls. The mixture of 〇 hours is obtained to obtain a slurry for green sheets. Further, for the 100 parts by weight of the calcined powder, the respective ratios of the solvent, the binder, and the plasticizer were 50 parts by weight, 5 parts by weight, and 2.5 parts by weight, respectively. Ο 涂布 Apply the obtained green sheet to the polyester film using the doctor blade method. After drying it, cut it into 5 〇 χ 〇 〇 〇 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳 彳The film (the semiconductor ceramic precursor layer is printed on the upper surface of the green sheet by a screen printing method to form an internal electrode precursor layer. Further, the average particle diameter relative to 1 part by weight is 〇. In the Ni powder of 2 (4), BaTiCh, which is an electrical insulating material, is added in an amount of 1 ounce to knead and kneaded to prepare a slurry for internal electrodes. Next, five green sheets in which an internal electrode precursor layer is formed are laminated on the upper surface thereof. The green sheet on which the internal electrode precursor layer is not formed is overlapped on the lower surface, so that the (4) machine is added to the direction of the buildup layer to obtain the transfer, and the male body is used to cut the I object, thereby having • At the time of 24·200908030, the binder was removed from the laminate. Then, the laminate was fired for 2 hours in a reducing environment of 1200 to obtain a porous sintered body. Further, the reducing environment was hydrogen and Nitrogen mixed environment, volume of hydrogen and nitrogen The ratio is 1:99 'The dew point of the mixed environment is 1 〇. 其次. Next, the sintered body is immersed in an aqueous solution of an alkali metal salt, whereby the alkali metal component is attached to the sintered body. The metal salt used has a molecular weight of 29.881. In addition, the concentration of the alkali metal (Li) in the aqueous solution of the metal salt (Li2〇) is 〇〇8 〇mol% in terms of alkali metal element (in terms of Li element). The sintered body is immersed in LLO. After the aqueous solution, the sintered body was dried at normal temperature for 1 hour. Then, the sintered body was reoxidized by heating in a nitrogen atmosphere for 2 hours to obtain the body 4. Next, The Ag-Pd slurry was applied to the end faces 4a, 4b of the body 4, and then sintered at 650 ° C in the atmosphere to form external electrodes & 5b. Thereby, a laminate of the composition shown in Fig. 1 was obtained. Type thermistor 1. (Examples 2 to 10) ί, β Substituted Li2〇, and the same procedure as in Example 1 except that the alkali metal salt shown in Table 1 was used as the alkali metal salt. Example 2~1〇 each laminated PTC thermistor. 1) A laminated PTC thermistor of Comparative Example was produced by the same method as in Example 1 except that the sintered body was not impregnated with the aqueous solution of the alkali metal salt. (Comparative Example 2) 131933.doc • 25· 200908030 The content of Μη(Ν03)2·6Η20 contained in the raw material powder is twice as large as in the case of Example 1 and the sintered body is not impregnated into the aqueous solution of the alkali metal salt. The layered PTC thermistor of Comparative Example 2 was produced in the same manner as in Example 1. The composition of the barium titanate-based compound contained in the semiconductor ceramic layer of Comparative Example 2 is as shown in the following formula (〇〇). (Ba〇.997Gd〇.〇〇3), 〇2Ti〇3 + 0.〇5Si〇2+0.002MnO ··· (l〇) (Comparative Examples 3, 4) Substituting an aqueous solution of an alkali metal salt, the sintered body Each of the laminated PTC thermistors of Comparative Examples 3 and 4 was produced in the same manner as in Example 除 except that the aqueous solution of the alkaline earth metal salt shown in the surface was impregnated. (Comparative Examples 5 to 7) Comparative Examples 5 to 7 were produced in the same manner as in Example 取代 except that the aqueous solution of the alkali metal salt was impregnated with the aqueous solution of the transition metal salt shown in Table 丨. Each of the laminated type ptc thermistors. (Comparative Example 8) Further, a powder of the metal salt NkCO3 was prepared as a raw material powder. With respect to 1 mol of the Ti element of the above formula (6), the mixed powder of Example 1 was contained in an amount of 0.0035 mol of Na2C〇3 powder in terms of an alkali metal element. Then, the layered PTC thermistor of Comparative Example 8 was produced by the same method as in Example 1 except that the sintered body was not impregnated with the aqueous solution of the alkali metal salt. (Comparative Example 9) Further, a powder of the metal salt NkCO3 was prepared as a raw material powder. With respect to 1 mol of the Ti element of the above formula (6), in the conversion of the metal element, the mixed powder of Example 13933.doc -26-200908030 is contained in the amount of Na2C〇 equivalent to the amount of πϋ·0005 m〇i. 3 powder. Then, a comparative example was produced by the same method as in the first example, the same method as in the first embodiment, except that the sintered body was not immersed in the aqueous solution of the alkali metal salt. 9 layered type (Comparative Example 10) After reoxidation, instead of re-serving the amount of k, the σ body is broken in the aqueous solution of the metal salt, in addition, Shishitian & by:, The laminated PTC thermistor of Comparative Example 10 was produced in the same manner as in Example 1.

[Measurement of void ratio] The porosity of the sintered body of the semiconductor ceramic layer constituting each of the obtained laminated PTC thermistors of Example 10 and Comparative Examples 1 to 10 was measured by a porosimeter. The measurement results are shown in Table 2. [Measurement of Resistivity] The resistivity (room temperature resistivity) R25 at 25 ° C was measured for each of the laminated PTC thermistors of the obtained Example 丨〇~丨〇 and Comparative Example 丨~〗 : Qcm), and the resistivity (high temperature resistivity) at 200 ° C. Further, the resistance change widths r2gg/R25 and logiodoo/R25 are obtained from the measured values of the room temperature resistivity R25 and the high temperature resistivity 仏(8). The measurement results of Examples 丨 to (7) and Comparative Examples ( to (9) are shown in Table 1. Further, the magnitude of the resistance change R2 〇 q / R25 is large, which means that the jump characteristic of the laminated PTC thermistor is large. Among the laminated type PFc thermistors, a small room temperature resistivity R25 is preferable, and a large high temperature resistivity loo and a resistance change range R2qq/R25 are preferable. 131933.doc •27- 200908030 [Table l] Metal salt (Note 1) Void ratio 25°C Resistivity 200°C Resistivity resistance change range Chemical formula molecular weight mol % (%) R25[Qcm] R200[Qcm] ^-20 (/^-25 l〇glO(R2〇[/^25 ) Comparative Example 1 Not impregnated - 14 2.33E+02 7.36E Ten 04 3.16E+02 2.5 Comparative Example 2 Not impregnated 14 1.00E+05 3.16E +08 3.16H+03 3.5 Example 1 Li20 29.881 0.08 14 2.40E+03 1.73E+08 7.23E+04 4.9 Example 2 NaOH 39.997 0.08 14 1.32E+03 3.55E+07 2.69E+04 4.4 Example 3 KOH 56.106 0.08 14 4.25E+03 1.21H+10 2.84E+06 6.5 Example 4 LiN03 68.946 0.08 14 4.26E+03 1.1 IE Ten 09 2.60E+05 5.4 Example 5 NaN03 84.995 0.08 14 2.30E+02 4.58E +07 2.00E+05 5.3 Example 6 Na2C03 105.988 0.08 14 9.75E+02 3.44E+07 3.53E+04 4.5 Example 7 Li2S04 109.946 0.08 14 5.36E+02 1.07E+07 1.99E+04 4.3 Example 8 Na2Si03 122.063 0.08 14 7.98E+02 2.34E+07 2.93E+04 4.5 Example 9 NkS04 142.043 0.08 14 4.37E+02 1.75E+06 4.01E+03 3.6 Example 10 n%b4o7 201.219 0.08 14 5.71E+02 4.61E+06 8.08E+03 3.9 Comparative Example 3 Ca(N03)2-4H20 164.0 88 0.08 14 4.81E+02 2.41E+05 5.01E+02 2.7 Comparative Example 4 CaCl2-2H20 110.983 0.08 14 6.78E+02 3.40E+05 5.01E+02 2.7 Comparative Example 5 CuS04*5H20 159.610 0.08 14 4.93E+ 06 2.46E+07 4.99E+00 0.7 Comparative Example 6 Zn(N03)2*6H20 189.400 0.08 14 3.33E+02 1.67E+05 5.01E+02 2.7 Comparative Example 7 Ni(N03)2-6H20 182.703 0.08 14 3 , 63E+02 1.82E+05 5.01E+02 2,7 Comparative Example 8 Not impregnated - 14 2.00E+09 2.00E+09 ]j 0 Comparative Example 9 Not impregnated - 14 1.74E+03 5.51E+05 3.16E+02 2.5 Comparative Example 10 Immersion after reoxidation 29.881 0.08 14 2.33E+02 7.37E+04 3.I6E+02 2.5 (Note 1) The concentration of metal salt (mol%) indicates the converted metal element in the aqueous solution ( Concentration of alkali metal elements, alkaline earth metal elements, and transition metal elements.

In Examples 1 to 10 in which the sintered body before reoxidation was immersed in an aqueous solution of an alkali metal salt, compared with Comparative Example 1 in which the sintered body was not impregnated with an aqueous solution of an alkali metal salt, it was confirmed that R200/R25 and Logl 0 (Κ·20〇/Κ·25) is larger. Further, in Examples 1 to 10, it was confirmed that the room temperature resistivity R25 was a small value which was practical. In Comparative Example 2, the values of R2GQ/R25 and l〇gl 0 (foot 20 〇 / ft 25) can be increased by changing the composition of the semiconductive ceramic layer, but if the sintered body is immersed in the alkali metal salt In comparison with Examples 1 to 10 of the aqueous solution, it was confirmed that r25 became extremely large. Examples 3 to 7 in which the sintered body before reoxidation is immersed in an aqueous solution of an alkaline earth metal salt or a transition metal salt, and an embodiment in which the sintered body before reoxidation is immersed in an aqueous solution of an alkali metal salt Compared with 1 to 10, it has been confirmed that -28-131933.doc 200908030 R2〇〇/R25 and l〇g1Q (R2()Q/R25) are small. In Comparative Examples 8 and 9 in which the metal salt Na2C03' was contained in the raw material roll and the sintered body was not immersed in the metal salt of the metal salt, the sintered body before reoxidation was immersed in the aqueous solution of the metal salt. For comparison, e confirms that rwr25 and logi〇 (R2〇〇/R25) are small. In Comparative Example 10 in which the sintered body was immersed in an aqueous solution of the metal salt after reoxidation, not reoxidation, in comparison with Example 10 in which the sintered body before reoxidation was immersed in an aqueous solution of an alkali metal salt It has been confirmed that R2〇〇/R25 and log丨0 (R2〇〇/R25) are small. Next, the composition of the main component was changed, and a laminated PTC thermistor was produced and evaluated. [Production of the laminated PTC thermistor] (Example 11) Bac03, Ti02, Gd203, and 205 were separately weighed in such a manner that the obtained barium titanate-based compound was composed of the following formula (11). After the powder, the raw material powder was mixed with pure water and a ball for pulverization in a container made of nylon for 6 hours, and then dried to obtain a mixed powder. (Ba〇.9985Gd〇.〇〇i5)〇.995(Ti〇.9985 Nb0.00J5)〇3 (n) A porous sintered body was produced in the same manner as in Example except that the mixed powder was used. Next, the obtained alkali metal salt is adhered to the sintered body by impregnating the obtained sintered body with an aqueous solution of an alkali metal salt. As the alkali metal salt, NaN〇3 having a molecular weight of 84.995 is used. In the conversion of alkali metal elements (in terms of Na element), the concentration of alkali metal (Na) in an aqueous solution of an alkali metal salt (NaN〇3) is 131933.doc -29- 200908030 is 0.08 mol% 〇 and then 'Ag-Pd slurry After being applied to the end faces 4a, 4b of the body 4, it is 650 in the atmosphere. (: Sintering was performed to form external electrodes 5a and 5b. Thereby, the laminated type thermistor 1 having the configuration shown in Fig. 1 was obtained. (Examples 12 to 3 4) As a metal salt solution, 0.08 mol% of NaN03 was substituted. Each of the laminated PTC thermistors of Examples 12 to 34 was produced in the same manner as in Example ji except that the aqueous solution was used as the aqueous solution of the alkali metal salt shown in Table 2. Ο (Example 35) The obtained barium titanate-based compound is a composition of the following formula (12). BaC03, TiO2, Gd203, Nb205, MnO, and Si〇2 are separately weighed as a raw material powder. In addition to the use of the above-mentioned raw material powder, and examples 12 The laminate type PTC thermistor of Example 35 was obtained in the same manner. (Ba〇.9985Gd〇.〇015), 02(Ti〇.9985 Nb〇.〇015)03+0.05Si02+0.〇〇1 MnO··· (12) (Comparative Example 11) The sintered body was not impregnated into the aqueous solution of the metal salt, and

Cj A laminated PTC thermistor of Comparative Example 丨i was obtained in the same manner as in Example 11. (Comparative Example 12) Further, a powder of an alkali metal salt NasCO3 was prepared as a raw material powder. The mixed powder of Example 11 is contained in an amount equivalent to 0.0035 mol in terms of a metal element in terms of 1 mol of the element of the above formula (11) (i.e., (TiG9985Nb〇〇川)]. NaaCO3 powder. Then, the laminated PTC thermistor of Comparative Example 12 was obtained by the same method as in Example 131 131933.doc • 30-200908030, except that the sintered body was not impregnated with the aqueous solution of the alkali metal salt. (Comparative Example 13) A powder of an alkali metal salt NasCOs was further prepared as a raw material powder. With respect to 1 mol of the element of the Ti position of the above formula (11) [ie, '(Ti〇9985Nb()(9)丨5)), the mixed powder of Example 11 is equivalent to 0.0005 mol in terms of metal element. Amount of Na2C〇3 powder. Then, the laminated PTC thermistor of Comparative Example 13 was obtained in the same manner as in Example 不 except that the sintered body was not impregnated with the aqueous solution of the alkali metal salt. (Comparative Example 1 4) BaC03, Ti〇2, Gd2〇3, Nb2〇5, MnO, and Si〇2 were separately prepared as the composition of the above formula (12) by the obtained barium titanate-based compound. Raw material powder. A layered PTC thermistor of Comparative Example 14 was produced in the same manner as in Comparative Example 12 except that the raw material powders were used. (Comparative Example 15) BaC03, Ti〇2, Gd2〇3, Nb205 and MnO were weighed in such a manner that the obtained barium titanate-based compound was a composition of the following formula (丨3). These raw material powders were mixed with pure water and pulverized balls in a container made of nylon for 6 hours, and then dried to obtain a mixed powder. (Ba〇.9985Gd〇.〇〇15)0 995(Tj〇9985 Nb〇.〇015)〇3+〇.〇〇2MnO ··· (13) The above mixed powder is used as a raw material, and the sintered body is not impregnated A layered PTC thermistor of Comparative Example 15 was obtained in the same manner as in Example 除 except that the mixture of the alkali metal water was used. [Measurement of void ratio] The sintered body of the semiconductor ceramic layer constituting each of the obtained laminated ptc thermistors of Examples i丨 to 35 and Comparative Examples 13l933.doc - 31 - 200908030 11 to 15 was measured by a porosimeter. Void rate. The measurement results are shown in Table 2. [Measurement of alkali metal content] Each of the laminated PTC thermistors of Examples 11 to 35 and Comparative Examples 11 to 15 obtained was measured by an icP (inductively coupled plasma) luminescence analyzer. The alkali metal equivalent amount (alkali metal content) of the alkali metal compound contained in the semiconductive ceramic layer. The measurement results are shown in Table 2. Further, the quantitative analysis result of the alkali metal by the ICP emission spectrometer was consistent with the amount of the alkali metal calculated by preliminarily filling the void of the sintered body with the aqueous solution of the alkali metal salt. [Confirmation of the fine structure] For each of the laminated PTC thermistors of Examples 1 to 35 and Comparative Example 5 obtained, a CMA X-ray microanalyzer (manufactured by JEOL Co., Ltd.: JXA8500F) was used to analyze the semiconductor ceramics. The fine structure of the layer 'disc recognizes whether or not the alkali metal element is unevenly distributed. The results after confirmation are shown in Table 2. In Table 2, the term "grain boundary and void portion" means that the alkali metal element is unevenly distributed in the grain boundary and the void portion. [Measurement of resistivity] With respect to the obtained examples u to 35 and the laminated electrolyte PTC thermistor of Comparative Example, the specific resistance at 25 [ [room temperature resistivity (R25), unit.ncni] and 200 ° C were measured. The resistivity [high temperature resistivity (R2〇.) | bit. Qcm]. Further, the resistance change range r_/R25 and l〇glO(R2〇〇/R25) 〇131933.doc •32· 200908030 [Table 2] \ Salt (Note 1) Metal content (Note 2) Void ratio (%) Sulfone metal distribution 25 °C resistivity (R25) [Qcm] 20 (TC resistivity (Κ·20〇) [Ωοηι] Resistance change formula Molecular weight mol % R200/R25 logio (R200/R25) Example 11 NaNO, 84.995 0.08 0.08 14 -- 6.66E+02 1.50E+08 2.25E+05 5.4 Example 12 NaNO, 84.995 0.04 0.04 14 -2 5^, To Chen Department of Grains, 1.64E+02 5.18E+07 3.16E+05 5.5 Example 13 NaNO, 84.995 0.02 0.02 14 --itp permanent grain edge technology, 3.26E+0I 9.46E+04 2.90 E+03 3.5 Example 14 NaN03 84.995 0.01 0.01 14 Grain boundary, middle 盹呻 2.40E+01 2.40E+04 1.00E+03 3.0 Example 15 NaOH 39.997 0.01 0.01 14 Grain edge, void * 3.00E +01 3.78E+04 1.26E+03 3.1 Example 16 NaOH 39.997 0.08 0.08 14 , void portion 1 nnF+mf\ ^ 1F+OR a 11 < Q Example 17 Na2C03 105.988 0.01 0.01 14 J. 〇 - ·»·.. ·χ»Ι^〇|* 5.UUE+U1 7.92E+04 1.58E+03 3.2 Example 18 Na2C〇T 105.988 0.08 0.08 14 Void 1.00E+03 7.94E+08 7 94E +05 5 9 Example 19 Na2Si03 122.063 0.01 0.01 14 'Voids 3.00E+01 3.00E+04 1.00E+03 3.0 Example 20 Na2Si03 122.063 0.08 0.08 14 Grain boundary, commanding part 7 OOF+Π? 1 7ΛΡ -Ι-Π» ^ A Example 21 Li20 29.881 0.01 0.004 14 Grain boundary, void portion 5.00E+01 7.92E+04 1 58E+03 3 2 Example 22 Li20 29.881 0.08 0.028 14 Grain boundary, Xintaodu 1.00E+03 5.01E+0S 5 01E+05 5 7 Example 23 LiOH 23.949 0.01 0.004 14 Grain boundary, void portion 5.00E+01 7.92E+04 1.58E+03 3.2 Example 24 LiOH 23.949 0.08 0.028 14 crystal Grain boundary, empty land 1.00E+03 7.94E+08 7.94E+05 5.9 Example 25 LiN03 68.946 0.01 0.004 14 Grain boundary, void region ΟΟΕ, ΟΟΕ+02 L58E+05 1.58E+03 3.2 Example 26 LiN03 68.946 0.08 0.028 14 Grain boundary, open space 1.00E+03 1.00E+09 1.00E Ten 06 6.0 Example 27 Li2S04 109.946 0.01 0.004 14 Grain boundary, void 2.00E+01 2.50E+04 1.00E+03 3.0 Example 28 Li2S04 109.946 0.08 0.028 14 Grain boundary, void portion 5.00E+02 6.29E+07 1.26E+05 5.1 Example 29 KOH 56.106 0.01 0.017 14 Grain boundary and void are 3.00E+01 3.00E+04 1.00E+03 3.0 Example 30 KOH 56.106 0.08 0.119 14 Grain boundary, void portion 1.00E+03 5.01E+08 5.01E+05 5.7 Example 31 kno3 101.11 0.01 0,017 14 Grain boundary, void portion 3.00E+01 3.00E+04 1.00E+03 3.0 Example 32 kno3 101.11 0.08 0.119 14 Grain boundary, void portion 5.00E+02 1.26E+07 2.51E+04 4.4 Example 33 k2co3 138.21 0.01 0.017 14 Grain boundary, void 3.00E+01 3.00E+04 1.00E+03 3.0 Example 34 K2C03 138.21 0.08 0.119 14 Grain boundary, void part 6.00E+02 9.51E+06 1.58E+04 4.2 Comparative Example 11 Not impregnated • • 0 14 None 2.30E+01 5.78E+02 2.51E+01 1.4 Comparative Example 12 Not impregnated • 0.08 14 Not sure (Note 3) 2.00E+09 2.00E+09 I.00E+00 0.0 Comparative Example 13 Not impregnated - • 0,01 14 Not sure (Note 3) 1.00E+02 1.00E+04 1.00E+02 2.0 Example 35 NaN03 84.995 0.04 0.04 14 Grain junction, void part 5.00E+03 7.92E+08 1 .58E+05 5.2 Comparative Example 14 Not impregnated - - 0,08 14 Not sure (Note 3) 2.00E+09 2.00E+09 1.00E+00 0.0 Comparative Example 15 Not impregnated - 0 14 No 1.00E+05 3.16E+07 3.16E+02 2.5 (Note 1) The concentration of the metal salt (mol%) indicates the concentration of the alkali metal element in the aqueous solution. (Note 2) indicates the alkali base of the barium titanate compound relative to the sintered body. The mass ratio (% by mass) of the metal element conversion. (Note 3) The alkali metal is not segregated in the sintered body, and the position of the alkali metal cannot be determined. "Grain boundary, void portion -33 - 131933.doc 200908030 The aqueous solution before the reoxidation is immersed in the aqueous solution of the test metal # In Example 1 3 5, the alkali metal element is unevenly distributed in the grain boundary and the gap portion of the sintered body. The laminated pTc thermistor (Examples 11 to 35) having such a structure can maintain a low room temperature resistivity and can be increased at the same time as compared with Comparative Example Π15 in which the sintered body is not impregnated with an aqueous solution of an alkali metal salt. Big jump special f students. Specifically, the room temperature resistivity (R25) of the laminated PTC thermistor of Example i 34 is ixi 〇 3 (iicm) or less, and the value of l 〇 gi 〇 (R2 〇〇 / R25) is 3 · 0 or more. Further, in the laminated PTC thermistor of Example 35, compared with Comparative Example 14 using the same barium titanate-based compound, the room temperature resistivity (R25) can be lowered and the jump characteristics can be increased. In Comparative Examples 12 to 14 in which the raw material powder contained the metal salt Na2C〇3 and the sintered body was not impregnated with the aqueous solution of the metal salt, the low room temperature resistivity and the large jump characteristic could not be achieved. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing a laminated PTC thermistor according to a preferred embodiment of the laminated PTC thermistor of the present invention. Fig. 2(A) is a photograph (1 〇〇〇〇) showing an example of the fine structure 〇〇 region of the semiconductor ceramic layer of the present invention. Fig. 2(B) is a diagram showing the sodium element distribution of ruthenium based on the semiconductor ceramic layer corresponding to the photograph of Fig. 2(A). Fig. 2(C) is a diagram showing the elemental distribution of germanium based on the semiconductor ceramic layer corresponding to the photograph of Fig. 2(A). Fig. 3 is a flow chart showing the steps of a preferred embodiment of the method for fabricating a laminated PTC thermistor of the present invention. 131933.doc -34. 200908030 [Description of main component symbols] 1 Laminated PTC thermistor 2 Semiconductor ceramic layer 3 Internal electrodes 3a, 3b Electrode end face 4 Main body 4a, 4b End face 5a ' 5b External electrode S11 Mixing step S12 Burning step S13 pulverization step S14 forming step S15 debonding step S16 firing step S17 alkali metal adhesion step S18 drying step S19 reoxidation step 131933.doc -35-

Claims (1)

200908030, Patent Application:: A laminated PTC thermistor, characterized in that: extremely = two bodies' alternately stacked with a semiconductor ceramic layer and an internal electrical end face two pairs of external electrodes, which are respectively disposed on the two bodies a facet and electrically connected to the internal electrode; the second body layer contains a crystal grain containing a copper phthalate compound, and the "body" alkali metal element is unevenly distributed on the day of the grain boundary And at least one of the void portions. 2. f Ο A method for manufacturing a laminated PTC thermistor, characterized in that a layer of a semiconductor layer containing a titanium-based compound and a layer of a ceramic layer containing a titanium-based compound are formed. a PTC thermistor, the manufacturing method comprising: a first step of forming an interlayer layer of the semiconductor ceramic layer precursor layer and the internal electrode precursor layer; and a second step, in a reducing environment Burning the above laminated body to form a porous sintered body; a third step of "attaching a metal component to the sintered body; and a fourth step of attaching the above metal to the test The method of manufacturing a laminated PTC thermistor according to claim 2, wherein in the third step, the solution containing the metal salt is attached to the sintered body. 4. The method of manufacturing a laminated PTC thermistor according to claim 3, wherein the alkali metal salt is selected from the group consisting of NaN〇3, NaOH, Na2ca3, 131933.doc 200908030 Na2Si03, A method of producing a laminated PTC thermistor according to claim 3 or 4, wherein the molecular weight of the alkali metal salt is at least one of a group consisting of Li20, LiOH, LiN03, Li2S04, KOH, ΚΝ〇3, and K2C03. 80~130. L 131933.doc -2-